Heattech is a line of clothing developed by Uniqlo that is designed to provide warmth without adding bulk. The fabric is made from a blend of materials that trap heat generated by the body, making it ideal for cold weather. Heattech garments are lightweight, soft, and comfortable, allowing for easy layering. The Heattech collection includes various items such as tops, leggings, and thermal underwear. These products are available in different styles and colors, catering to diverse fashion preferences while ensuring warmth. Heattech technology is also moisture-wicking, helping to keep the wearer dry and comfortable throughout the day.